12v fridge and electric step

[Pagen]

is there a possible connection between our dometic fridge not working on 12 v and the step not going out as I switch off the ignition and not retracting on starting the vehicle? Both faults seemed to appear at same time ?

 

[obanvanman]

The fridge should only work on 12v when the engine is running/ignition on. When you turn the ignition off it should be working on either gas or mains if on EHU. Someone else may come along with a solution but I would go looking for the fuse for the step.
But then again I am on my 3rd gin, so what do I know?

 

[Mikeco]

My fridge and step are wired into the same relay but that was my choice and I suppose that it could be on yours. Don’t understand why your step goes out when you turn off the ignition though as that would not make sense.

 

[two]

Yes (a disconnection). It may be that the signal to the step to come in when the ignition is switched on may be used to switch the fridge to 12V (also lower a sat dish). I'd look for a blown fuse, but could not say where you might find it.

 

[Pagen]

Thanks for your suggestions peeps. Just to clarify the step used to self extend as and when I turned the engine off. When I started the engine the step would retract. Neither of these functions happen via the ignition now but the step can be operated via its button or by setting or unsetting the ducato s alarm. The fridge works fine on 230 or gas. It used to work on 12 v when engine running. There is a fuse box behind drivers seat an em 50 Sargent box thingy and I notice fuses in their relating to both fridge and step so tentatively made a vague connection. I believe there are relays in there too.

^{_{Subscribers  do not see these advertisements}}

 

[Lenny HB]

The fridge should only work on 12v when the engine is running/ignition on. When you turn the ignition off it should be working on either gas or mains if on EHU.

Depends on the van most German vans you can run the fridge off the hab batteries all the vans I have had you can.

Thanks for your suggestions peeps. Just to clarify the step used to self extend as and when I turned the engine off. When I started the engine the step would retract. Neither of these functions happen via the ignition now but the step can be operated via its button or by setting or unsetting the ducato s alarm. The fridge works fine on 230 or gas. It used to work on 12 v when engine running. There is a fuse box behind drivers seat an em 50 Sargent box thingy and I notice fuses in their relating to both fridge and step so tentatively made a vague connection. I believe there are relays in there too.

The fuse box behind the drivers seat is probably the feeds from the alternator D+ this gives a 12v output when the engine is running and they use it to switch the fridge & step relays. Need to check 12v is present on the fuses when the engine is running. The problem could be any of, blown fuse, faulty relay, faulty wiring or faulty alternator. Often there is a electronic distribution box connected to the D+ so that the D= output from the alternator does not get overloaded. In Motorhomes quite a lot of things are often run from the D+, sept, fridge relay, split charge relay, side marker lights etc.

 

[mike mcglynn]

On my old van an Autotrail the relay for the fridge and step was near the cab battery and so was the fuse for it, it was in a small holder with a clear plastic top and an easy job to sort ,

 

[138go]

Sure I read somewhere that someone’s D+ wire ran under the front cab mat and the connector had been crushed so was not making contact. You could do with a wiring diagram to find colour codes etc.

 

[Pagen]

Sorry chaps what is D+ and D= ? Not sure what they stand for?

 

[Pagen]

Also meant to say are relays easy to identify and replace if necessary?

^{_{Subscribers  do not see these advertisements}}

 

[xsparks]

My van uses the same fuse to withdraw the step and run the fridge when ignition turned on to stay engine. Fuse is in engine compartment. 15amp.

 

[jockaneezer]

D+ as I understand it, is the signal the alternator gives out, once the engine is running to let you know it's producing voltage. This is the signal that switches off the red charge light on your dashboard of your car/van when you start it up, so it's useful for activating/deactivating items that need to know that the engine is running (steps, fridges etc). It's not designed to carry a lot of current, so usually operates a relay or relays to operate the relative functions. These relays sometimes play up by completely failing or sticking in the on position.

 

[Pagen]

Are relays repairable or easily changed ?

 

[denisejoe]

Fridge should only work on gas after switching of engine + 10 minuites

 

[xsparks]

Relays plug in.But are usually very reliable.

^{_{Subscribers  do not see these advertisements}}

 

[tonyidle]

Are relays repairable or easily changed ?

Normally easy to change but rarely faulty. The common item that affects both fridge and step relays (there will be a relay for each) is, as already mentioned, the D+ feed. Check the Sargent circuit diagram for its location. There should be 12v on it only when the engine is running.

 

[xsparks]

Mine used separate contacts on the same relay. Obviously when the engine is started the step needs to rise and the fridge start on 12v.

 

[Phantomphixer]

Are relays repairable or easily changed ?

Generally speaking relays are fairly reliable. The faults presented by relays, typically are. High resistance contacts (dirty or burnt contacts, normally means although the relay works mechanically, electrically the switching function does not work). Welded contacts, where the current flowing, together with high resistance contacts means the resultant heat generated welds the contacts together (generally identified by the relay being permanently on). Open circuit (burnt out) coil, in which case although the supply is present at the relay coil, it does not function at all. (Relays generally make an audible 'Click' when pulling in or dropping out).
Often it's the first. In which case you can generally open the relay case. (however today a lot are permenantly sealed). Remove the relay from the supply (unplug) first. At the base of the relay you can often see the joint where the cover clips onto the base and also a couple of dimples where the case locates. With a small screwdriver or something similar you can pry the case off. Check the contacts and if burnt and blackened using a FINE emery paper or board gently clean the contacts then refit the case. I would only recommend you do this in the case of an emergency, and treat it as a temporary fix. Relay contacts have a coating and a special action that keeps them clean ... Ish! Their mechanisms can be fairly delicate. Cleaning the contacts can remove the surface of the contacts which to be fair is probably damaged anyway. Also only attempt this if you have positively identified the faulty relay first!

I think that's relays mostly covered, there are of course other faults but these are the most common.